The invention pertains to a thermomagnetic recording head and to its mode of embodiment, which is particularly well-suited to making very closely packed stacks of magnetic recording heads.
The recording head of the invention can be applied, with particular advantage, to devices that require high-density data recording, whether parallel or sequential. A head of this kind may, for example, be used in a magnetic tape recorder.
As a rule, a magnetic head must develop a field of approximately 1000 Oe, i.e. 80 mA/micrometer. It is difficult to set up such a field by means of a single current turn, and it is thus necessary to make a coil. Hence, a recording head, even one made in the form of a thin film, is a device which cannot be integrated with a pitch of less than 100 micrometers, and this is inadequate for high-density recording.
Acoustical solutions have been proposed, but they do not give the necessary resolution: a resolution of 10 micrometers would correspond to an acoustical pass-band of at least 200 MHz, whereas the magnetostrictive effects do not follow this particular frequency.
Thermomagnetic action gives high frequencies which may attain 1 MHz and enables integration with a typical pitch of 10 micrometers in devices operating by Joule effect and 1 micrometer in devices operating by optical image formation.
There are known devices of this kind in which the recording medium has a relatively low Curie point and enables recording by thermomagnetic action.
But such devices require a recording medium that is adapted to have a Curie point of this degree.
The purpose of the invention is to mitigate the deficiencies of the Prior Art.
The invention can be used to make recordings, by thermomagnetic action, on magnetic media such as standard quality magnetic tapes where the Curie point is not necessarily low.